[wasm] Embedder can control what buffers wasm compilation works on.

src/wasm/wasm-js.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/api-natives.h"
 #include "src/api.h"
 #include "src/asmjs/asm-js.h"
 #include "src/asmjs/asm-typer.h"
 #include "src/asmjs/asm-wasm-builder.h"
 #include "src/assert-scope.h"
@@ skipping 61 matching lines @@
     thrower->TypeError("Argument 0 must be a buffer source");
   }
   if (start == nullptr || end == start) {
     thrower->CompileError("BufferSource argument is empty");
   }
   return {start, end};
 }
 
 static i::MaybeHandle<i::WasmModuleObject> CreateModuleObject(
     v8::Isolate* isolate, const v8::Local<v8::Value> source,
-    ErrorThrower* thrower) {
+    ErrorThrower* thrower, bool async) {
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
-  i::MaybeHandle<i::JSObject> nothing;
+  i::MaybeHandle<i::WasmModuleObject> nothing;
+
+  AllowWasmCompileCallback callback =
+      reinterpret_cast<i::Isolate*>(isolate)->allow_wasm_compile_callback();
+  if (callback != nullptr && !callback(source, async)) {
+    thrower->RangeError(
+        "Wasm compilation disallowed in this context for provided argument");

[bradnelson, 2017/02/18 00:28:42]

How about:
Wasm compilation exceeds internal limits in this context for provided arguments

[Mircea Trofin, 2017/02/18 00:41:47]

Done.

+    return nothing;
+  }
 
   RawBuffer buffer = GetRawBufferSource(source, thrower);
   if (buffer.start == nullptr) return i::MaybeHandle<i::WasmModuleObject>();
 
   DCHECK(source->IsArrayBuffer() || source->IsTypedArray());
   return i::wasm::CreateModuleObjectFromBytes(
       i_isolate, buffer.start, buffer.end, thrower, i::wasm::kWasmOrigin,
       i::Handle<i::Script>::null(), i::Vector<const byte>::empty());
 }
 
@@ skipping 37 matching lines @@
   if (!v8::Promise::Resolver::New(context).ToLocal(&resolver)) return;
   v8::ReturnValue<v8::Value> return_value = args.GetReturnValue();
   return_value.Set(resolver->GetPromise());
 
   if (args.Length() < 1) {
     thrower.TypeError("Argument 0 must be a buffer source");
     resolver->Reject(context, Utils::ToLocal(thrower.Reify()));
     return;
   }
   i::MaybeHandle<i::JSObject> module_obj =
-      CreateModuleObject(isolate, args[0], &thrower);
+      CreateModuleObject(isolate, args[0], &thrower, true);
 
   if (thrower.error()) {
     resolver->Reject(context, Utils::ToLocal(thrower.Reify()));
   } else {
     resolver->Resolve(context, Utils::ToLocal(module_obj.ToHandleChecked()));
   }
 }
 
 void WebAssemblyValidate(const v8::FunctionCallbackInfo<v8::Value>& args) {
   v8::Isolate* isolate = args.GetIsolate();
@@ skipping 20 matching lines @@
   HandleScope scope(isolate);
   ErrorThrower thrower(reinterpret_cast<i::Isolate*>(isolate),
                        "WebAssembly.Module()");
 
   if (args.Length() < 1) {
     thrower.TypeError("Argument 0 must be a buffer source");
     return;
   }
 
   i::MaybeHandle<i::JSObject> module_obj =
-      CreateModuleObject(isolate, args[0], &thrower);
+      CreateModuleObject(isolate, args[0], &thrower, false);
   if (module_obj.is_null()) return;
 
   v8::ReturnValue<v8::Value> return_value = args.GetReturnValue();
   return_value.Set(Utils::ToLocal(module_obj.ToHandleChecked()));
 }
 
 MaybeLocal<Value> InstantiateModuleImpl(
     i::Isolate* i_isolate, i::Handle<i::WasmModuleObject> i_module_obj,
-    const v8::FunctionCallbackInfo<v8::Value>& args, ErrorThrower* thrower) {
+    const v8::FunctionCallbackInfo<v8::Value>& args, ErrorThrower* thrower,
+    bool as_promise) {
   // It so happens that in both the WebAssembly.instantiate, as well as
   // WebAssembly.Instance ctor, the positions of the ffi object and memory
   // are the same. If that changes later, we refactor the consts into
   // parameters.
   static const int kFfiOffset = 1;
 
   MaybeLocal<Value> nothing;
   i::Handle<i::JSReceiver> ffi = i::Handle<i::JSObject>::null();
   // This is a first - level validation of the argument. If present, we only
   // check its type. {Instantiate} will further check that if the module
   // has imports, the argument must be present, as well as piecemeal
   // import satisfaction.
   if (args.Length() > kFfiOffset && !args[kFfiOffset]->IsUndefined()) {
     if (!args[kFfiOffset]->IsObject()) {
       thrower->TypeError("Argument %d must be an object", kFfiOffset);
       return nothing;
     }
     Local<Object> obj = Local<Object>::Cast(args[kFfiOffset]);
     ffi = i::Handle<i::JSReceiver>::cast(v8::Utils::OpenHandle(*obj));
   }
+  AllowWasmInstantiateCallback allow_instantiate =
+      i_isolate->allow_wasm_instantiate_callback();
+  if (allow_instantiate != nullptr &&
+      !allow_instantiate(Local<WasmCompiledModule>::Cast(Utils::ToLocal(
+                             i::Handle<i::JSObject>::cast(i_module_obj))),
+                         Utils::ToLocal(ffi), as_promise)) {
+    thrower->RangeError(
+        "WebAssembly Instantiation is not permitted in this context");

[bradnelson, 2017/02/18 00:28:42]

How about:
Wasm instantiation exceeds internal limits in this context for provided
arguments

[Mircea Trofin, 2017/02/18 00:41:47]

Done.

+    return nothing;
+  }
 
   i::MaybeHandle<i::JSObject> instance =
       i::wasm::WasmModule::Instantiate(i_isolate, thrower, i_module_obj, ffi);
   if (instance.is_null()) {
     if (!thrower->error())
       thrower->RuntimeError("Could not instantiate module");
     return nothing;
   }
   DCHECK(!i_isolate->has_pending_exception());
   return Utils::ToLocal(instance.ToHandleChecked());
@@ skipping 86 matching lines @@
 void WebAssemblyInstance(const v8::FunctionCallbackInfo<v8::Value>& args) {
   HandleScope scope(args.GetIsolate());
   v8::Isolate* isolate = args.GetIsolate();
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
   ErrorThrower thrower(i_isolate, "WebAssembly.Instance()");
 
   auto maybe_module = GetFirstArgumentAsModule(args, &thrower);
 
   if (!maybe_module.is_null()) {
     MaybeLocal<Value> instance = InstantiateModuleImpl(
-        i_isolate, maybe_module.ToHandleChecked(), args, &thrower);
+        i_isolate, maybe_module.ToHandleChecked(), args, &thrower, false);
 
     if (instance.IsEmpty()) {
       DCHECK(thrower.error());
       return;
     }
     args.GetReturnValue().Set(instance.ToLocalChecked());
   }
 }
 
 void WebAssemblyInstantiate(const v8::FunctionCallbackInfo<v8::Value>& args) {
@@ skipping 24 matching lines @@
     thrower.TypeError(
         "Argument 0 must be a buffer source or a WebAssembly.Module object");
     resolver->Reject(context, Utils::ToLocal(thrower.Reify()));
     return;
   }
   bool want_pair =
       !HasBrand(first_arg, i::Handle<i::Symbol>(i_context->wasm_module_sym()));
   i::Handle<i::WasmModuleObject> module_obj;
   if (want_pair) {
     i::MaybeHandle<i::WasmModuleObject> maybe_module_obj =
-        CreateModuleObject(isolate, args[0], &thrower);
+        CreateModuleObject(isolate, args[0], &thrower, true);
     if (!maybe_module_obj.ToHandle(&module_obj)) {
       DCHECK(thrower.error());
       resolver->Reject(context, Utils::ToLocal(thrower.Reify()));
       return;
     }
   } else {
     module_obj = i::Handle<i::WasmModuleObject>::cast(first_arg);
   }
   DCHECK(!module_obj.is_null());
   MaybeLocal<Value> instance =
-      InstantiateModuleImpl(i_isolate, module_obj, args, &thrower);
+      InstantiateModuleImpl(i_isolate, module_obj, args, &thrower, true);
   if (instance.IsEmpty()) {
     DCHECK(thrower.error());
     resolver->Reject(context, Utils::ToLocal(thrower.Reify()));
   } else {
     DCHECK(!thrower.error());
     Local<Value> retval;
     if (want_pair) {
       i::Handle<i::JSFunction> object_function = i::Handle<i::JSFunction>(
           i_isolate->native_context()->object_function(), i_isolate);
 
@@ skipping 549 matching lines @@
   i::Handle<i::Symbol> symbol(isolate->context()->wasm_memory_sym(), isolate);
   return HasBrand(value, symbol);
 }
 
 bool WasmJs::IsWasmTableObject(Isolate* isolate, Handle<Object> value) {
   i::Handle<i::Symbol> symbol(isolate->context()->wasm_table_sym(), isolate);
   return HasBrand(value, symbol);
 }
 }  // namespace internal
 }  // namespace v8